# Value Sources (API, Oracle)

**`set_collection_value_source(...)`**: Assigns an API endpoint or oracle address as the value source.

When **`is_api_source = true`**, metadata or NFT values may depend on data fetched from this endpoint.

When **`is_api_source = false`**, the source is considered an oracle address providing on-chain data feeds.

This feature enables dynamic NFTs that can reflect external states or real-world conditions.


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.artinals.com/artinals-protocol/art20/openapi.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.